package com.lulei.geo; 
 
import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.HashMap; 
import java.util.List; 
 
import com.lulei.geo.bean.LocationBean; 
import com.lulei.util.JsonUtil; 
 
public class GeoHash { 
 private LocationBean location; 
 /** 
  * 1 2500km;2 630km;3 78km;4 30km 
  * 5 2.4km; 6 610m; 7 76m; 8 19m 
  */ 
 private int hashLength = 8; //经纬度转化为geohash长度 
 private int latLength = 20; //纬度转化为二进制长度 
 private int lngLength = 20; //经度转化为二进制长度 
  
 private double minLat;//每格纬度的单位大小 
 private double minLng;//每个经度的单位大小 
 private static final char[] CHARS = {'0', '1', '2', '3', '4', '5', '6', '7', 
    '8', '9', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 
    'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'}; 
 private static HashMap<Character, Integer> CHARSMAP; 
  
 static { 
  CHARSMAP = new HashMap<Character, Integer>(); 
  for (int i = 0; i < CHARS.length; i++) { 
   CHARSMAP.put(CHARS[i], i); 
  } 
 } 
  
 public GeoHash(double lat, double lng) { 
  location = new LocationBean(lat, lng); 
  setMinLatLng(); 
 } 
  
 public int gethashLength() { 
  return hashLength; 
 } 
  
 /** 
  * @Author:lulei 
  * @Description: 设置经纬度的最小单位 
  */ 
 private void setMinLatLng() { 
  minLat = LocationBean.MAXLAT - LocationBean.MINLAT; 
  for (int i = 0; i < latLength; i++) { 
   minLat /= 2.0; 
  } 
  minLng = LocationBean.MAXLNG - LocationBean.MINLNG; 
  for (int i = 0; i < lngLength; i++) { 
   minLng /= 2.0; 
  } 
 } 
  
 /** 
  * @return 
  * @Author:lulei 
  * @Description: 求所在坐标点及周围点组成的九个 
  */ 
 public List<String> getGeoHashBase32For9() { 
  double leftLat = location.getLat() - minLat; 
  double rightLat = location.getLat() + minLat; 
  double upLng = location.getLng() - minLng; 
  double downLng = location.getLng() + minLng; 
  List<String> base32For9 = new ArrayList<String>(); 
  //左侧从上到下 3个 
  String leftUp = getGeoHashBase32(leftLat, upLng); 
  if (!(leftUp == null || "".equals(leftUp))) { 
   base32For9.add(leftUp); 
  } 
  String leftMid = getGeoHashBase32(leftLat, location.getLng()); 
  if (!(leftMid == null || "".equals(leftMid))) { 
   base32For9.add(leftMid); 
  } 
  String leftDown = getGeoHashBase32(leftLat, downLng); 
  if (!(leftDown == null || "".equals(leftDown))) { 
   base32For9.add(leftDown); 
  } 
  //中间从上到下 3个 
  String midUp = getGeoHashBase32(location.getLat(), upLng); 
  if (!(midUp == null || "".equals(midUp))) { 
   base32For9.add(midUp); 
  } 
  String midMid = getGeoHashBase32(location.getLat(), location.getLng()); 
  if (!(midMid == null || "".equals(midMid))) { 
   base32For9.add(midMid); 
  } 
  String midDown = getGeoHashBase32(location.getLat(), downLng); 
  if (!(midDown == null || "".equals(midDown))) { 
   base32For9.add(midDown); 
  } 
  //右侧从上到下 3个 
  String rightUp = getGeoHashBase32(rightLat, upLng); 
  if (!(rightUp == null || "".equals(rightUp))) { 
   base32For9.add(rightUp); 
  } 
  String rightMid = getGeoHashBase32(rightLat, location.getLng()); 
  if (!(rightMid == null || "".equals(rightMid))) { 
   base32For9.add(rightMid); 
  } 
  String rightDown = getGeoHashBase32(rightLat, downLng); 
  if (!(rightDown == null || "".equals(rightDown))) { 
   base32For9.add(rightDown); 
  } 
  return base32For9; 
 } 
 
 /** 
  * @param length 
  * @return 
  * @Author:lulei 
  * @Description: 设置经纬度转化为geohash长度 
  */ 
 public boolean sethashLength(int length) { 
  if (length < 1) { 
   return false; 
  } 
  hashLength = length; 
  latLength = (length * 5) / 2; 
  if (length % 2 == 0) { 
   lngLength = latLength; 
  } else { 
   lngLength = latLength + 1; 
  } 
  setMinLatLng(); 
  return true; 
 } 
  
 /** 
  * @return 
  * @Author:lulei 
  * @Description: 获取经纬度的base32字符串 
  */ 
 public String getGeoHashBase32() { 
  return getGeoHashBase32(location.getLat(), location.getLng()); 
 } 
  
 /** 
  * @param lat 
  * @param lng 
  * @return 
  * @Author:lulei 
  * @Description: 获取经纬度的base32字符串 
  */ 
 private String getGeoHashBase32(double lat, double lng) { 
  boolean[] bools = getGeoBinary(lat, lng); 
  if (bools == null) { 
   return null; 
  } 
  StringBuffer sb = new StringBuffer(); 
  for (int i = 0; i < bools.length; i = i + 5) { 
   boolean[] base32 = new boolean[5]; 
   for (int j = 0; j < 5; j++) { 
    base32[j] = bools[i + j]; 
   } 
   char cha = getBase32Char(base32); 
   if (' ' == cha) { 
    return null; 
   } 
   sb.append(cha); 
  } 
  return sb.toString(); 
 } 
  
 /** 
  * @param base32 
  * @return 
  * @Author:lulei 
  * @Description: 将五位二进制转化为base32 
  */ 
 private char getBase32Char(boolean[] base32) { 
  if (base32 == null || base32.length != 5) { 
   return ' '; 
  } 
  int num = 0; 
  for (boolean bool : base32) { 
   num <<= 1; 
   if (bool) { 
    num += 1; 
   } 
  } 
  return CHARS[num % CHARS.length]; 
 } 
  
 /** 
  * @param i 
  * @return 
  * @Author:lulei 
  * @Description: 将数字转化为二进制字符串 
  */ 
 private String getBase32BinaryString(int i) { 
  if (i < 0 || i > 31) { 
   return null; 
  } 
  String str = Integer.toBinaryString(i + 32); 
  return str.substring(1); 
 } 
  
 /** 
  * @param geoHash 
  * @return 
  * @Author:lulei 
  * @Description: 将geoHash转化为二进制字符串 
  */ 
 private String getGeoHashBinaryString(String geoHash) { 
  if (geoHash == null || "".equals(geoHash)) { 
   return null; 
  } 
  StringBuffer sb = new StringBuffer(); 
  for (int i = 0; i < geoHash.length(); i++) { 
   char c = geoHash.charAt(i); 
   if (CHARSMAP.containsKey(c)) { 
    String cStr = getBase32BinaryString(CHARSMAP.get(c)); 
    if (cStr != null) { 
     sb.append(cStr); 
    } 
   } 
  } 
  return sb.toString(); 
 } 
  
 /** 
  * @param geoHash 
  * @return 
  * @Author:lulei 
  * @Description: 返回geoHash 对应的坐标 
  */ 
 public LocationBean getLocation(String geoHash) { 
  String geoHashBinaryStr = getGeoHashBinaryString(geoHash); 
  if (geoHashBinaryStr == null) { 
   return null; 
  } 
  StringBuffer lat = new StringBuffer(); 
  StringBuffer lng = new StringBuffer(); 
  for (int i = 0; i < geoHashBinaryStr.length(); i++) { 
   if (i % 2 != 0) { 
    lat.append(geoHashBinaryStr.charAt(i)); 
   } else { 
    lng.append(geoHashBinaryStr.charAt(i)); 
   } 
  } 
  double latValue = getGeoHashMid(lat.toString(), LocationBean.MINLAT, LocationBean.MAXLAT); 
  double lngValue = getGeoHashMid(lng.toString(), LocationBean.MINLNG, LocationBean.MAXLNG); 
  LocationBean location = new LocationBean(latValue, lngValue); 
  location.setGeoHash(geoHash); 
  return location; 
 } 
  
 /** 
  * @param binaryStr 
  * @param min 
  * @param max 
  * @return 
  * @Author:lulei 
  * @Description: 返回二进制对应的中间值 
  */ 
 private double getGeoHashMid(String binaryStr, double min, double max) { 
  if (binaryStr == null || binaryStr.length() < 1) { 
   return (min + max) / 2.0; 
  } 
  if (binaryStr.charAt(0) == '1') { 
   return getGeoHashMid(binaryStr.substring(1), (min + max) / 2.0, max); 
  } else { 
   return getGeoHashMid(binaryStr.substring(1), min, (min + max) / 2.0); 
  } 
 } 
  
 /** 
  * @param lat 
  * @param lng 
  * @return 
  * @Author:lulei 
  * @Description: 获取坐标的geo二进制字符串 
  */ 
 private boolean[] getGeoBinary(double lat, double lng) { 
  boolean[] latArray = getHashArray(lat, LocationBean.MINLAT, LocationBean.MAXLAT, latLength); 
  boolean[] lngArray = getHashArray(lng, LocationBean.MINLNG, LocationBean.MAXLNG, lngLength); 
  return merge(latArray, lngArray); 
 } 
  
 /** 
  * @param latArray 
  * @param lngArray 
  * @return 
  * @Author:lulei 
  * @Description: 合并经纬度二进制 
  */ 
 private boolean[] merge(boolean[] latArray, boolean[] lngArray) { 
  if (latArray == null || lngArray == null) { 
   return null; 
  } 
  boolean[] result = new boolean[lngArray.length + latArray.length]; 
  Arrays.fill(result, false); 
  for (int i = 0; i < lngArray.length; i++) { 
   result[2 * i] = lngArray[i]; 
  } 
  for (int i = 0; i < latArray.length; i++) { 
   result[2 * i + 1] = latArray[i]; 
  } 
  return result; 
 } 
  
 /** 
  * @param value 
  * @param min 
  * @param max 
  * @return 
  * @Author:lulei 
  * @Description: 将数字转化为geohash二进制字符串 
  */ 
 private boolean[] getHashArray(double value, double min, double max, int length) { 
  if (value < min || value > max) { 
   return null; 
  } 
  if (length < 1) { 
   return null; 
  } 
  boolean[] result = new boolean[length]; 
  for (int i = 0; i < length; i++) { 
   double mid = (min + max) / 2.0; 
   if (value > mid) { 
    result[i] = true; 
    min = mid; 
   } else { 
    result[i] = false; 
    max = mid; 
   } 
  } 
  return result; 
 } 
  
 
 public static void main(String[] args) { 
  // TODO Auto-generated method stub 
  GeoHash g = new GeoHash(40.221227, 116.24875); 
  String geoHash = g.getGeoHashBase32(); 
  System.out.println(geoHash); 
  LocationBean bean = g.getLocation(geoHash); 
  System.out.println(JsonUtil.parseJson(bean)); 
  System.out.println(new GeoHash(bean.getLat(), bean.getLng()).getGeoHashBase32()); 
  System.out.println(DistanceUtil.getDistance(bean.getLat(), bean.getLng(), bean.getLat() - g.minLat, bean.getLng() - g.minLng)); 
 } 
 
}